The R of the title stands for the young protagonist, Rune, fearlessly played by Pilou Asbæk. Imprisoned for violent assault, hes a cocky, good-looking young man placed in the hardcore ward, where his survival depends on quickly learning the prisons parallel world of rules, honor, and obligations. R also stands for Rachid, a young Muslim prisoner who becomes Runes friend and accomplice, defying the rigid racial stratifications among the inmates.